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E. T. GILLILAND.

LOOPING- IN SWITCH.

Patented Feb. 23, 1886.

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UNITED STATES PATENT OFFICE.

EZRA T. GILLILAND, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF SAME PLACE LOOPING-IN SWITCH.

SPECIFICATION forming part of Letters Patent No. 336.563, dated February 23, 1886.

Application filed October 3l, 1885.

.To @ZZ whom it may concern,.-

Beit known that I, EZRA T. GILLILAND, residing at Boston, in the county of Suffolk and State of Massachusetts` have invented certain Improvements in Looping in Switches, of which the following is a specification.

Thisinvention, called a looping in switch, is an improved combination of apparatus to be located in the central ofiice of a telephoneexchange. Its arrangement is such that by the depression of one of two buttons a listening telephone may be introduced into atelephonecircuit; by the depression of' the second button the said telephone is introduced into a second circuit; by the depression of both buttons simultaneously the telephone is looped into the circuit of two connected lines, and by imparting a rotary movement to a button a call is transmitted on one line or the other, de pending upon which of the buttons is operated and upon the connection of the flexible conducting cords in the circuit of which the apparatus is normally included.

Figure l shows a section of a multiple switch-board to which my improvement is applied. Fig. 2 is a detail plan View of the looping-in mechanism.

C C are two strips of spring-brass, to which fieXible conducting-cords c c are respectively connected. These strips rest by their resilience upon two stops, s s', respectively connected to opposite terminals of the clearingout annunciator A.

t t are strips of spring-brass, to which the opposite terminals of the operators telephoneset T are respectively connected.

E is a similar strip of spring-brass connected to ground. Its free end is covered with a plate of insulating material, i, in connection with E, and fixed near its free end is a metal bar, b, overlapping springs t t, but normally out of contact therewith.

G is a fixed metal post to which a grounded generator of electricity is connected.

G indicates a type of generator that may be used, though obviously any generator suitable for signaling purposes may be employed.

P P indicate the controlling-keys, consisting of buttons of insulating material fixed to the ends of spindles,whieh are placed in bear- Serial No. 181,525. (No model.)

ings so that they can either be moved longitudinally or rotated. Upon the opposite ends of these spindles are ixed disks d d', of metal, having a sector removed therefrom. The post G is located within the circumferential line of both disks. Upon the under side of disks d d are cam-shaped projections It. One disk overllps springs C, t. and E, and the other overlaps C, t, and E. NVhen button P is depressed it carries with it strips t' and E. The bar I) on E, making electrical Contact with strip t, grounds said strip. W'hen P is depressed, the same is true as regards t; E, and t', respectively. Vhen both P and P' are simultaneously de* pressed, the relative position of t, E, and t is unchanged, and neither t nor t are grounded. The spindles are held in their normal position against longitudinal Amotion by the resilience ot' the iiat spring -pieces' which they overlap. and from rotary movement by helical spring S.

The apparatus is placed in position upon t-he table of a switchboard, as shown at P P, Fig. l. Vhen a call is indicated, one of the cord-tips, as c', is inserted in ajack, asj, and the button P depressed. The depression of P carries with it springs C', t', and E, breaks contact between C and s', makes contact between C', d, and t', and between E and t. Circuit then is via elements c' C d t T t E to ground. The telephone is thus placed in the calling-subscriber@ circuit. Cord c is now placed in the called-for circuit and a rotary movement given to button P.. The cam 7c on disk d travels upon the surface of C, depressing it, breaking contact between C and s, and making contact between G and C, P being rotated until that edge of the disk left by the removal of the sector strikes generator-post G. Button P immediately resumes its normal position, and the telephone T may be inserted by depressing P in the same manner and to the same effect as described in respect to P. Connection is now complete, the circuit being cia C s A s C c.

To loop the telephone set T into the com- .pound circuit, both buttons P P are simultaneously depressed. This breaks the connection with s s and makes connection between C4 and t and C' and t', respectively. In this IOO g@ ceases manner I make two press-buttons perform the functions now performed by two press-buttons and two switch-levers.

What I claim, and desire to secure by Letters Patent, is-

1. A looping-in device for a telephone-exchange, consisting of the combination of two movable contacts in the circuit of a pair of conducting-cords, two movable contacts connected to opposite terminals of a telephone, a movable ground-contact, and two controllingkeys, by the operation of which two or more of said movable contacts may be connected together and to the ground, either or both.

2. A looping-in device consisting of two movable contacts included in the circuit of a pair of conducting-cords, two movable electrical contacts, to which the terminals of a telephone are respectively connected, a movable ground-contact, a fixed generatorcontaet, and two controllingkeys,whereby twQ or more of said movable contacts may be connected together, or either ot' the iirstnamed contacts connected with the generator.

8. The combination, in a telephone eX change, of two tlat spring-contacts in the circuit oi'a pair of conducting-cords, two similar flat spring-contacts respectively connected to the opposite terminals of a telephone, a flat spring connected to ground, and a pair ofcoutrolling-keys, as P P', for inserting the tele phone with respect to either or both of two connected circuits.

4. The combination of a pair of spring-contacts in circuit with connecting cords and plugs, a pair of rotatable buttons or keys having each a disk partly cut away, and a cam on said disk, and a grounded generatorpost within the circumferential line of both said disks, whereby the normal circuit of either of said springs may be broken and connection made with the generator, substantial] y as described.

5. A looping-in switch comprising, in combination, a pair of contacts in circuit with conducting cords and plugs, a pair of movable contacts forming terminals ofatelephonecircuit, a movable gr0und-contact, a grounded generatorcontact, and a pair of controllingkeys comprising each a spindle having rotary and longitudinal movements, and a conducting disk or plate, all of said contacts being under the control of one, and said ground and generator contacts being under the control of both, said controlling-keys, substantially as described.

6. In a loopingin switch, the combinationv of a separable electrical contact in the circuit of a conducting cord and plug, an electrical contact connected with a generator, an electrical contact connected with atelephone, and a controllingkey capable of rotation and depression, one movement establishing connection between the cord and generator-contact, and the other establishing connection between the cord and telephone-contact7 substantially as described.

In testimony whereofI have signed my name to this specitication, in the presence of two subscribing witnesses, this 5th day ofOctober, 1885.

EZBA T. GILLILAND.

Vitnesses:

WM. B. VANsIzE, GEo. WILLIs PIERCE. 

